I have a whining sound comming of the front of the car(Hyunday accent 2000)I think myself that it is comming from the front brake,that has not the thicknes annymore 16 mm instead of 19mm

Sounds like something let go inside the engine, have a shop inspect it.

I think your problem may be MICE. Check your upper and lower O2 Sensor wires. I believe they are both 4 wire sensors. If a wire has been chewed through this is what happens. I personally had this problem myself once in my 2000 Hyundai Accent. GOOD LUCK.

one bolt goes though from the starter side and the other goes in though the transmission housing and screws into the starter. You may need to remove the aircleaner housing to get down into the area that the bolt head is in.

There are a couple of things to cause metallic sounds when turning. First thing, is if it's a clicking sound when you turn, then you have a cv joint going bad. It's usually more prominent when moving in reverse, however it can happen just as well while moving forewards. Secondly, if it's more of a grinding or scraping noise, we have a couple of options. The sound could be coming from the brakes, if they're worn or have grit stuck in them, or it could be bad bearings in the front wheel hub. The wheel hub has a tendency to making a whining noise when driving; usually most easily heard when driving past buildings. They can also allow the tire/wheel to present the appearance of leaning when looking at it. If bad enough, it can even rub on the brake caliper, or cause the disc brake rotor to wear out the brake pads prematurely. So, to recap: Check:
CV joints, if a clicking sound brakes or wheel hub bearings if grinding or whining sound.

Go to www.hmaservice.com and register( Vehicle by VIN). Afterward, you have access to shop manuals, service bulletins, wiring diagrams, etc. about your vehicle.

The intermittence and the air sound leads me to believe that this is most likely a bad brake booster/and or master cylinder. The master cylinder is easy enough to replace (you just have to remember to bench bleed the cylinder and still bleed the brakes because you inevitably get air in them) but have changed a booster myself. I've heard its not bad if you know what you're doing but don't really know myself. 

It sounds to me as if your serpentine belt and/or belt tensioner is bad,
I had a similar problem on my s10 and replaced belt,idler & tensioner.
All three pieces ran about $80.00. I did the work myself. Hope this helps.

Check the condition of front disc brake pads, if they are in need of replacement a preset little metal arm starts rubbing the discs and will make a whining noise. It doesn't do any damage but it's irritating to listen to.

As we can see in figure below it sit vertically up in the front of the car.

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http://www.hmaservice.com/
Get user name, password and login. On page click ETM and select model ie accent MC ,year 2002, G 1.6DOHC.